1. Field of the Invention
The invention concerns a composting device which produces high-quality compost without the necessity to turn over the organic material.
2. Description of the Prior Art
Organic material for composting is usually stacked in piles on the ground. Compost ready for harvesting is always found right at the bottom of pile, making it necessary to use a gardening tool such as a fork or shovel to get to the matured organic material under the heap. This entails much physical effort especially as the compost usually weighs at least 100 kilograms. One must first remove the unripe material from the pile and place it aside the heap so that the mature compost can be removed.
In many composting instruction manuals from the manufacturers of conventional compost equipment, the harvesting of part or all of the ready-to-use compost is described as easy. For instance, the company Otto Graf Gmbh, in Tennington, Germany stated in their brochure that “the removal of compost is very simple: small amounts are taken out through the side slide-openings. When one needs to remove larger amounts, it is more comfortable to follow the following procedure: take off the entire cylinder—put the upper layer with the active micro-organisms to one side—clear away the finished compost from the floor-plate—clean the grooves for the cylinder in the floor-plate. Put the cylinder back on and refill it from above with the unready compost”. This quote from Otto Graf GmbH serves as an example for many other compost makers such as Alko company, whose web-site can be seen on http://www.alko.de/garten-hobby/gartenforum/haeko/umsetzen.html.
Heaps stored on the floor are only ventilated at the sides, which has two further disadvantages. Firstly, micro-organisms living in the inner part of the compost heap suffer from a constant lack of air. This is only alleviated by periodically turning the pile over. After only a day, if pile is not turned over the air deficit reoccurs. Secondly, in the centre of the heap, putrefaction zones develop causing very bad odours. Furthermore the micro-organisms can only work poorly due to the lack of air, and much more slowly than when there is a sufficient supply of air. In trials it has been shown that optimal ventilation of compost heaps increases composting performance by three to four times.
Compost heaps placed on the ground, have long been used for making one's own compost. The usual composter available on the market using the above-described method of composting is essentially nothing other than containers of compost heaps. It is often made of plastic, wood, or metal, can be round, square or pyramid shaped and mostly has a lid at the top for filling and a door at the bottom for removing the mature compost. It is however often more difficult to use than an initial inspection may indicate for physical reasons.
Some devices such as W00140140 have ventilation nozzles in the middle to improve aeration at the core of the heap and/or a 1-4 cm high floor perforated with small holes (Graf Schnellkomposter). The ventilation nozzles and the perforated floor improve the air supply only so long as the holes and the lower double floor underneath are blocked with fine ripe compost because the desired total vertical aeration of the heap away from the floor cannot be achieved. In both cases further turning over of the heap cannot be avoided and is necessary.
Many attempts have been made to reduce the physical effort involved in turning compost over using mechanically operated scraping, jogging, scratching components and the like over a grille. What all these devices have in common is that the material can only be obtained through the grille using moving parts (DE-A1 27 37 421, AT-A 320 688, AT-A 346 375 among others). The problem in this case is that the expense involved for an ordinary household is too great.
On the other hand SE 520325 is simpler, where a grille on which the compost lies, is moved manually. EP 1118604 and NZ248540 use divider panels which are pulled in and out by hand and require once again physical effort from the user, as is also the case for DE 4314786 which has divider bars which must be pulled out.
Compost in the compost drum used in EP 1348682 is well aerated and mixed through rotation of the drum by moving an external axle. This technology however is considerably more expensive than conventional home composting devices and also involves physical exertion from the user.
The Rototherm compost maker from the Juwel company in Imst, Austria is described as follows on its home page on http://www.juwel.com/k_e1_frame.html: “Turning compost over is no longer necessary! Through easy-to-use intelligent technology low-smelling compost can be obtained very quickly. Both the laborious and not always hygienic turning over and sieving for fine particles required when using conventional compost makers is completely unnecessary.” The turning over is achieved by moving a spirally-shaped stirrer over a perforated plate. Whether this mincing principle, where the screw lies close up to the cylinder wall functions, the container being 100 cm in diameter is still debatable. In any case physical effort is still required to operate the apparatus, and moreover, the cost is far too high for the purposes of home composting and is about four times more expensive than a conventional composter.
In order to work, Patent EP 0485 358 B1 requires dry and crumbly mature compost rather than “sticky” raw compost which would lead to formation of bridges or arches on the grille causing residual material to remain in the decomposition chamber (column 2 lines 39-58).
It was attempted to shorten the time necessary to attain a crumbly composition by adding compost worms to the compost to solve the problem of bridge formation on the grille in order to speed up the process. However, despite intensive experiments carried out using a 50 m3 experimental container, the requisite dry and crumbly state in accordance with EP 0485 358 B1 could not be reached within a reasonable time. The compost crumbled on the grille only at the beginning, until arch-like bulges and bridges formed on the grille, after which the pile came to a standstill and the ready but still sticky compost could not without assistance reach the storage chamber.
Over time, compost mineralises and becomes more crumbly. This however requires much more time using EP 0485 358-B1 even with the addition of compost worms—than the new invention to be described later, which produces good quality compost that can be successfully used in the garden after a period of only 6 to 8 weeks decomposition with good ventilation.
Furthermore, when using conventional composters, a dryer state can only be achieved reasonable quickly if over a longer period of time no further organic material is added to the top of the heap, which hardly seems practical given the amount of biological refuse continually produced by an average household. The reason for this is that organic waste consists of 70% water. This water tends to seep down into the container and so keeps the compost underneath wet.
It was therefore necessary to take up the challenge which was not only to produce dry and crumbly compost in the storage chamber, but to obtain compost in the shortest possible period after about 6-8 weeks rotting time when the material is not yet dry and crumbly by means of a device in the storage chamber and at the same time avoid the bridge effect described previously. Moreover, the apparatus should neither involve turning over the compost heap nor require any physical movement of the device by the user, as is necessary in other technological solutions such as those presented above. Apart from this, it should be relatively cheap to produce which seems especially important for those people wishing to make their own compost.